基于新城疫病毒V蛋白鉴别鸡群感染与免疫的间接ELISA方法的建立

本研究以新城疫病毒(NDV)V蛋白羧基端结构域(Vc)的重组蛋白为包被抗原,建立了用于检测NDV V蛋白抗体的间接ELISA方法,并采用该方法检测了鸡群免疫或接毒后血清中的V蛋白抗体水平。结果显示:两组不同NDV灭活疫苗组在免疫后的3周内检测结果均为阴性;两组灭活疫苗免疫3周后再人工感染NDV强毒的鸡群,攻毒后第7、14和21 d,NDV阳性率分别为60%、80%、70%和50%、80%、70%;两组不同的NDV弱毒疫苗免疫组鸡群,仅在免疫后第21 d阳性率分别为20%和10%。以上结果表明,NDV疫苗免疫组与强毒感染组的V蛋白抗体阳性率存在明显差异,本方法可在群体水平上区分新城疫疫苗免疫与强毒感染鸡群,为NDV血清学诊断和流行病学调查提供了一种新的检测手段。

DEVELOPMENT OF INDIRECT ELISA BASED ON V PROTEIN OF NEWCASTLE DISEASE VIRUS FOR DIFFERENTIATING INFECTED FROM VACCINATED CHICKENS

In the present study,the recombinant protein of Newcastle disease virus(NDV)V protein C-terminal domain(Vc)was used as the coating antigen of indirect ELISA method for use in differentiating infected from vaccinated animals(DIVA)program.Chickens were vaccinated with two different inactivated NDV vaccines and none of the tested serum samples were positive.These chickens were challenged with virulent NDV strain at 21 days post vaccination and serum samples were collected and tested using this ELISA method.As a result,the chickens vaccinated with one vaccine showed the positive rates at 60%,80%and 70%and other chickens vaccinated with another vaccine had the positive rates at 50%,80%and 70%on days 7,14 and 21 post challenge.However,other chickens vaccinated with two different live attenuated NDV vaccines showed the positive rates at 20%and 10%on the day 21 post vaccination.These results suggested a signifi cant difference in the V protein antibody response between the chickens vaccinated with inactivated NDV vaccines and those challenged with virulent NDV strain.Therefore,this method might be used for DIVA program at the population level.